The urgent need for energy from cost-effective renewable energy sources is well recognized. Enhanced Geothermal Systems (EGS) and some hydrocarbon recovery systems rely on engineered reservoirs, bores, or wells introduced into the earth surface to recover energy producing materials from beneath the earth's surface including geothermal water, geothermal heat, hydrocarbon gases, and/or petroleum. However, recovering energy-producing materials from subterranean bedrock or shale rock beneath the earth's surface is not easily achieved currently or in a cost-effective or efficient manner due to a lack of permeability in the native bedrock at depths, e.g., between about 3 km to about 10 km. Furthermore, bedrock must be extensively fractured to provide necessary heat exchange or to provide accessibility for fluid volumes at flow rates that sustain EGS and some hydrocarbon recovery systems. However, to date, EGS systems have yet to attain sustainable flow rates, production rates, and/or yields needed for economic viability. Technological advances could render EGS systems viable for energy production within the US and worldwide and address untold energy needs in the future.
Hydraulic fracturing is a process of forcing a fracturing liquid under pressure into the reservoir to fracture subterranean shale rock or bedrock and introduce fissures or openings that allow energy-producing materials to be extracted and recovered. Hydraulic fracturing employs millions of gallons of water per well. Pressurized fracturing liquids may include various chemical modifiers that when injected at high pressure into the open fissures in the bedrock enhance the properties of the fracturing liquid and, in the case of unconventional hydrocarbon recovery systems, assist the recovery of oil and gas when released from the shale rock or bedrock. For example, modifiers including petrochemicals, surfactants, and macropolymers may be introduced in a fracturing fluid to modify the rheological properties of the bedrock or shale rock to promote fracturing of the bedrock, a process called “stimulation”. Chemical modifiers can modify or adjust the viscosity of the fracturing fluid, enhance performance of the fracking fluid, or otherwise increase the accessibility of the fracturing fluid into the bedrock or shale rock. Fractures and fracture-induced fissures introduced into the bedrock are held open during or following the fracturing treatment by injecting a proppant such as sand, ceramics, or bauxite in the fracking fluid. Addition of proppants allows petroleum and hydrocarbon gases such as methane (CH4) gas or other recovered energy-producing materials to diffuse or flow out of fractures and fissures into the reservoir for recovery. In EGS, proppants allow the working fluid to flow at a desired rate which allows heat to be extracted. However, well-known problems exist with conventional fracking fluids. For example, proppants including sand and other solid particulates degrade pumping components and piping over time reducing equipment lifetimes. Proppant particles can also constitute a high volume fraction of the fracturing fluid that can increase the density of the fracturing fluid. Highly viscous fluids or gels are often required to transport the dense proppants through the reservoir into the bedrock. Dense and heavy proppants when introduced can cause excessive loads on injection pumps and increase costs for pumping. In addition, chemicals introduced in fracturing fluids can leach into aquifers and contaminate the ground water or deleteriously impact the environment where reservoirs are located. Others can be carcinogenic or can include explosives or other high-energy compounds that themselves are problematic or otherwise require extreme or careful handling. Further, fracturing fluids developed for oil/gas recovery may not be applicable for geothermal recovery due to the fact that temperatures greater than 150° C. can degrade process chemicals. Finally, injected chemical additives and drilling mud can also be physically difficult to remove from the bedrock formation once a new fracture front is formed resulting in decreased flow rates and decreased heat transfer. Accordingly, new fracturing fluids, proppants, and processes are needed that enhance fracturing, permeability, and/or recovery of energy producing materials at high temperature and high pressure conditions. The present invention addresses these needs.